Over 37,000 Americans died in motor vehicle crashes in 2016, a 5.6% increase over the previous year — when deaths rose by 8.4%. The last time deaths caused by traffic accidents increased as much was in 1986.

According to several official sources, the increase in fatalities can be attributable, at least in part, to more drinking and driving and a greater overall number of people on the road, thanks to consistently low gas prices. But nationwide, traffic fatalities vary considerably across states.

While factors outside of the control of drivers, such as weather and road conditions, can increase or lower the risk of injury, much of the regional differences in traffic fatalities have to do with driver choice.

EverQuote, an online car insurance shopping service, produces EverDrive, an app that allows drivers to monitor their driving habits, including phone use, speeding, risky braking, acceleration, and turning. Using data from app users, EverQuote published “The 2016-2017 EverDrive Safe Driving Report.” The report grades each state according to driver safety habits — habits that could have life or death implications.

The report found an interesting correlation. The states where drivers are less likely to break the speed limit or otherwise engage in dangerous behavior actually have higher roadside fatality rates. On the other hand, states where drivers engage in risky behavior more often have lower car accident fatality rates. This has more to do with state laws such as speed limits and state geographical makeup, such as urban versus more rural states.